You Spin Me Right Round

Spin-off is a loaded term. In TV, spin-off series are usually direct derivatives of what they came from, like <i>The Flash</i> emerging from <i>Arrow</i> after Barry Allen appeared on the latter show. In comics, they can have direct connections, or just be “inspired” by a previous hero.
<p>Many of the characters on this list have recently started new series, showing their staying power, and some have even spun-off characters of their own!
<p>While Falcon and the new female Thor don’t quite qualify as spin-offs, since they’re more about replacing the character than supplementing them, they did get us thinking about this unique category. Unlike sidekicks or legacy heroes who work entirely under the direction of a mentor, or take on the identity of an older hero, spin-off characters are often fully functional in their own right, leading their own stories, having their own adventures, and sometimes remaining almost wholly separate from the characters that inspired them.

The Young Marvels

<p>Even though many people have historically thought of Captain Marvel - or Shazam, as he's now known - as a Superman clone, his history with spin-off characters actually predates the Man of Steel's by almost two decades.
<p>Though his first spin-offs, the Lieutenant Marvels, came around in 1941, they never caught on as well as Captain Marvel, Jr. who debuted later that year, or Mary Marvel, who first appeared in 1942.
<p>While they often acted as Cap's sidekicks, Cap Jr. and Mary quickly gained popularity in their own right, with Captain Marvel, Jr.'s costume famously influencing some of Elvis Presley's more flamboyant costumes, and Mary Marvel acting as a key player in several modern DC Comics stories.

X-23

<p>X-23 is a relatively recent addition to this list, having occupied the Marvel Universe since only 2004, but in that time, she's garnered a considerable cult following and an ever-increasing profile in the company's line.
<p>A clone of Wolverine who first appeared in the X-Men: Evolution cartoon, X-23 is a teenage girl with all of Wolverine's powers, trained as a master assassin and taken in by the X-Men. With a pedigree like that, it's no wonder why she's so popular.
<p>Aside from her time with the X-Men, X-23 has starred in several solo titles over the years, as well as stints with the Avengers Academy, and in the <b>Avengers Arena</b>. Recently, she defected over to Cyclops's squad, and is now training with the time displaced original X-Men, and has even toyed with some romantic entanglements with the characters on that team.

Batwoman

There have been several characters under the mantle of Batwoman over the years. The first, introduced in the late '50's, was Katherine Kane, a young socialite who became enamored of Batman and took to a life of adventuring. She even had her own sidekick, the original Batgirl, and lasted until the '70's, though her popularity waned in later years.
<p>Later, in 2006, a completely new Batwoman was introduced in the pages of DC's company-wide event <b>52</b>. This Batwoman's popularity was immediately apparent, and a big media push from DC helped raise awareness of the character and her sexuality. While this character was named Kate Kane, issues of <i>Batman, Inc.</i> revealed that a new version of the original Katherine Kane is still active in the DC Universe, albeit not as Batwoman.
<p>Batwoman eventually took over <i>Detective Comics</i> for a short time before finally receiving her own solo title as part of the New 52. Recently, Batwoman was the subject of some controversy when her longtime creative team left the book over DC's refusal to allow her to marry her long-term partner, Maggie Sawyer, citing the company's reluctance to allow any of its characters to marry at this time. Her solo title continues with a new creative team.

Hawkgirl

<p>Like her partner Hawkman, Hawkwoman has numerous incarnations over the years. Her Golden Age identity, Shiera Hall, may have been the first spin-off style character, joining the already active Hawkman in 1940, before eventually joining him in the JSA. Shiera Hall was briefly reintroduced after <i>Blackest Night</i> saw yet another death and resurrection of the Hawks.
<p>When DC Comics revived many of its properties in the '50's and '60's, a new Hawkman and Hawkgirl were introduced. Rather than being reincarnated Egyptian warriors like the originals, these characters were alien police officers from the planet Thanagar who had come to Earth. This version of Hawkgirl was later reintroduced as a Thanagarian named Hawkwoman after DC's rebooted continuity erased these versions of the characters.
<p>The most recent version, Kendra Saunders, was unique in that she became Hawkgirl at a time when there was no active Hawkman. She was a founding member of the re-formed JSA, and also eventually held down her own solo title. After Hawkman eventually did return, Kendra was reluctant to embrace her role as his soulmate, She eventually joined the JLA before her death in Blackest Night lead to her replacement by a reincarnated Shiera Hall.
<p>There is no Hawkgirl or Hawkwoman on the main "New 52" Earth, but a new Hawkgirl <i>has</i> emerged, over on Earth 2.

Spider-Woman

<p>Though she was created to prevent another company from using the name Spider-Woman as a reaction to Marvel's Spider-Man, Jessica Drew, AKA Spider-Woman, quickly saw her own popularity skyrocket, which lead to a 50-issue solo title in the '70's.
<p>After Jessica Drew was seemingly killed in a battle with her arch-enemy Morgan LeFay, she was replaced by Julia Carpenter, an unrelated character with different powers. Carpenter was a long time fixture in the West Coast Avengers, appearing in such major stories as <i>Secret Wars</i>, and even briefly serving as a member of the government's anti-mutant task force, Freedom Force.
<p>Eventually, Jessica Drew was brought back by Brian Bendis and placed on the New Avengers, a revamped Avengers team formed in the wake of the original Avengers' dissolution. Since her return, she has anchored a solo-series, and has remained a fixture of the Avengers roster for almost a decade.

Supergirl

<p>Supergirl was originally presented in 1959 as Superman's cousin, one of the few survivors of Krypton's demise. After a handful of stories featuring one-off female versions of Superman - usually Lois Lane or another supporting character given temporary powers - Otto Binder and Al Plastino introduced this first permanent version of the character. Interestingly, Binder had also created Mary Marvel years earlier, the female counterpart to Captain Marvel. Supergirl also starred in her own feature film in the early '80's.
<p>After the original Supergirl died at the hands of the Anti-Monitor in DC's continuity altering Crisis on Infinite Earths, the rebooted DC made an executive decision to remove all other survivors of Krypton from it's continuity, effectively rendering Superman Krypton's sole survivor. While Supergirl returned, it was in the guise of the Matrix, an strange construct from an alternate Earth that took Superman's form in homage.
<p>After the Matrix Supergirl's story became increasingly convoluted, DC eventually reintroduced Kara Zor-El, a version of the original Supergirl, who went on to star in several volumes of her own solo title, even adventuring with the Legion of Super-Heroes. This version of Supergirl was rebooted and reintroduced in the New 52 relaunch with a new solo title. She has just recently also joined the Red Lantern Corps as their newest member.

She-Hulk

<p>One of the last characters created by Stan Lee before his first retirement from comics, She-Hulk is really Jennifer Walters, a cousin of Bruce Banner who received Gamma powers after a blood transfusion from Banner. She possesses all of Hulk's strength and stamina, but usually remains relatively in control, if a bit uninhibited, when in Hulk form.
<p>Unlike Banner, Walters often chooses to remain She-Hulk, preferring her life as a super-hero to that of her mousy, shy alter-ego. Interestingly, Walters still often practices law as She-Hulk, proving her intelligence and strength go hand in hand. She has also served as an Avenger numerous times, and even as a substitute member of the Fantastic Four, a role she is currently filling in FF.
<p>She-Hulk has also starred in several solo titles over the years which often involve humorous, or fourth-wall-breaking elements. Her newest series recently launched as part of the All-New Marvel NOW! initiative.

Superboy

Though when he was introduced in 1945, Superboy was simply a teenage version of Superman detailing the hero's adventures taking place before his initial introduction, over the years he developed a mythos and supporting cast all his own, including Ma and Pa Kent, the Legion of Super-Heroes, and numerous other characters and concepts that would eventually be folded into the adult Superman's world.
<p>Over the years, several other versions of Superboy were introduced from alternate realities, but the most prominent was Superboy Prime, a version of Clark Kent from a wholly mundane world who helped save existence from the Anti-Monitor before returning as a villain decades later in Infinite Crisis before being wiped from continuity himself as part of the New 52 relaunch.
<p>In the '90's, on the heels of a relatively successful Superboy TV show and the apparent death of Superman, DC introduced a version of Superboy that was completely separate from Clark Kent. This version had slightly different powers, and was created as a clone using the DNA of Superman and Lex Luthor. After several solo series and a stint on the Teen Titans, this version, Kon-El, or Conner Kent, was killed doing battle with Superboy Prime.
<p>Kon-El was later resurrected before DC's New 52 relaunch re-wrote his history, introducing a vastly different version of the character in his own new series. This one was a clone of the son of Clark Kent and Lois Lane from a possible future. Of course, that wasn't complicated enough, and Kon was killed by the real Jon Lane Kent, who is now impersonating Kon as Superboy back in the present day.

Batgirl

Over the years, there have been numerous characters that have gone by the name Batgirl, just like Batwoman. The first, Betty Kane, was the niece of Katherine Kane, the original Batwoman. Though her adventures ended in the '60's, Betty was later reintroduced as Bette Kane, AKA Flamebird, an ally of the Teen Titans.
<p>In the '60's, DC Comics struck a deal to produce a Batman TV show with ABC. While the show was hugely popular, it became notorious in later years for its campiness, and humorous tone. Despite its dubious legacy, the show and comics did simultaneously introduce a new Batgirl, Barbara Gordon. The daughter of Batman's ally Commissioner Gordon, Barbara took to crime fighting without Batman's blessing before eventually earning his trust. Barbara Gordon, in the comics, remained Batgirl until being paralyzed by the Joker in the story The Killing Joke.
<p>After Barbara's paralysis, she took on the identity of Oracle, a master information broker, and the hub of Batman's network of allies. In this time, other characters took the mantle of Batgirl, the longest running of which was Cassandra Cain, who later took the mantle of Black Bat when longtime Batman ally Stephanie Brown took on the mantle of Batgirl. When DC relaunched its line with the New 52, Batgirl was given a new title starring Barbara Gordon, healed of her paralysis and operating once again as Batgirl.

Ms. Marvel

Though at this point she's technically a legacy character, having assumed the mantle of her mentor Captain Marvel, initially, and for many years, Carol Danvers was Ms. Marvel, a human Air Force pilot granted strange powers by the Psyche Magnetron, a weapon built by the alien Kree.
<p>After gaining her powers in an altercation with the Kree, Ms. Marvel trained and adventured with Captain Marvel - not the Shazam version, by the way, this one is at Marvel Comics - becoming a longtime Avenger and a capable hero in her own right before being forced into early retirement by an encounter with the mutant Rogue who permanently absorbed her memories and some of her powers. For a time, Carol became Binary, a stellar-powered ally of the X-Men and the space-faring Starjammers.
<p>In the '90's, Carol regained her memories and original powers. Rejoining the Avengers, she quickly became Marvel's premiere female hero, occasionally leading Earth's Mightiest Heroes, and starring in her own solo title. After a series of life events and major conflicts caused her to reevaluate her role as a hero, Carol finally ditched the Ms. Marvel name, taking on the identity of Captain Marvel. Captain Marvel's series relaunched with a fresh #1 and an interstellar mission as part of All-New Marvel NOW!
<p>Meanwhile, the Ms. Marvel title has passed onto a new character, Kamala Khan, who had her Inhuman powers activated at the end of the <i>Infinity</i> crossover.